''Xanthoparmelia conspersa'', commonly known as the peppered rock-shield, is a
foliose lichen
Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This partnership allows lichen to live in diverse ...
and the
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
of genus ''
Xanthoparmelia
''Xanthoparmelia'' (commonly known as green rock shields or rock-shield lichens) is a genus of foliose lichen in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ''Xanthoparmelia'' is syn ...
''. It is widely distributed in
temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
zones, and has been recorded from Japan, Europe, Africa, North America, and South America.
Taxonomy
The lichen was first
described with the name ''Lichen conspersus'' in 1799 by lichenologist
Erik Acharius
Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the taxonomy of lichens and is known as the "father of lichenology." Acharius was famously the last pupil of Carl Linnaeus.
Life
Acharius was born in ...
.
In its taxonomic history, it has been transferred to the genera ''Imbricaria'', ''
Lobaria
''Lobaria'' is a genus of foliose lichens, formerly classified in the family Lobariaceae, but now placed in the Peltigeraceae. They are commonly known as "lung wort" or "lungmoss" as their physical shape somewhat resembles a lung, and their ecol ...
'', and ''
Parmelia Parmelia may refer to:
* Parmelia (barque), the vessel that in 1829 transported the first settlers of the British colony of Western Australia
* ''Parmelia'' (fungus), a genus of lichens with global distribution
* Parmelia, Western Australia
Pa ...
''.
It became known as a species of ''Xanthoparmelia'' when
Mason Hale
Mason Ellsworth Hale, Jr. (September 23, 1929 – April 23, 1990) was one of the most prolific lichenologists of the 20th century. Many of his scholarly articles focused on the taxonomy of the family Parmeliaceae. Hale was one of the first liche ...
promoted that subgenus of ''Parmelia'' to generic status in 1974.
It is
commonly known as the "peppered rock-shield".
Description
''Xanthoparmelia conspersa'' has a
thallus
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...
that is either tightly or loosely attached to its substrate. The thallus, which measures , is made of narrow lobes that are 1–3 mm wide, which are crowded and usually overlapping. The thallus upper surface often features
isidia
An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...
that range in shape from spherical to branched cylinders. The lower surface of the thallus is black, except for near the lobe tips, where it may be pale to dark brown.
Rhizine
In lichens, rhizines are multicellular root-like structures, arising mostly from the lower surface. A lichen with rhizines is termed rhizinate, while a lichen lacking rhizines is termed erhizinate. Rhizines serve only to anchor the lichen to their ...
s are coarse, black, and simple (i.e., unbranched), with a length of 0.5–1 mm.
Ascospore
An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...
s are 5–6 by 9–10
μm.
Some
secondary metabolites
Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the nor ...
found in ''Xanthoparmelia conspersa'' include
usnic acid
Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species with the formula C18H16O7. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933-1937 by Curd and Robertson. Usnic a ...
,
hyposalazinic acid,
stictic and
norstictic acid
Norstictic acid is a depsidone produced as a secondary metabolite
Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fun ...
.
Habitat and distribution
''Xanthoparmelia conspersa'' grows on rocks (on
siliceous rock
Siliceous rocks are sedimentary rocks that have silica (SiO2) as the principal constituent. The most common siliceous rock is chert; other types include diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, or ...
s, particularly
granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
), and is typically found in sunny habitats.
It has been recorded from Asia (Japan), Europe, Africa, North America, and South America.
See also
*
List of ''Xanthoparmelia'' species
References
{{Taxonbar, from=Q10542533
conspersa
Lichen species
Lichens described in 1799
Lichens of Africa
Lichens of Europe
Lichens of Japan
Lichens of North America
Lichens of South America
Taxa named by Erik Acharius